package com.example.usercenter.config.security;

/**
 * Created by ZXN on 2018/9/30.
 */

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.servlet.InstrumentedFilter;
import com.codahale.metrics.servlets.MetricsServlet;
import com.example.usercenter.config.properties.AppProperties;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.server.MimeMappings;
import org.springframework.boot.web.server.WebServerFactory;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.http.MediaType;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;

import javax.servlet.*;
import java.nio.charset.StandardCharsets;
import java.util.EnumSet;

/**
 * Configuration of web application with Servlet 3.0 APIs.
 */
@Configuration
public class WebConfig implements ServletContextInitializer, WebServerFactoryCustomizer<WebServerFactory> {
    private final Logger log = LoggerFactory.getLogger(WebConfig.class);

    private final Environment env;

    private MetricRegistry metricRegistry;

    private AppProperties appProperties;

    public WebConfig(AppProperties appProperties, Environment env) {
        this.appProperties = appProperties;
        this.env = env;
    }

    @Override
    public void customize(WebServerFactory server) {
        setMimeMappings(server);
    }

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        if (env.getActiveProfiles().length != 0) {
            log.info("Web application configuration, using profiles: {}", (Object[]) env.getActiveProfiles());
        }
        EnumSet<DispatcherType> disps = EnumSet.of(DispatcherType.REQUEST, DispatcherType.FORWARD, DispatcherType.ASYNC);
        initMetrics(servletContext, disps);
        log.info("Web application fully configured");
    }

    private void setMimeMappings(WebServerFactory server) {
        if (server instanceof ConfigurableServletWebServerFactory) {
            MimeMappings mappings = new MimeMappings(MimeMappings.DEFAULT);
            // IE issue, see https://github.com/jhipster/generator-jhipster/pull/711
            mappings.add("html", MediaType.TEXT_HTML_VALUE + ";charset=" + StandardCharsets.UTF_8.name().toLowerCase());
            // CloudFoundry issue, see https://github.com/cloudfoundry/gorouter/issues/64
            mappings.add("json", MediaType.TEXT_HTML_VALUE + ";charset=" + StandardCharsets.UTF_8.name().toLowerCase());
            ConfigurableServletWebServerFactory servletWebServer = (ConfigurableServletWebServerFactory) server;
            servletWebServer.setMimeMappings(mappings);
        }
    }

    /**
     * Initializes Metrics.
     */
    private void initMetrics(ServletContext servletContext, EnumSet<DispatcherType> disps) {
        log.debug("Initializing Metrics registries");
        servletContext.setAttribute(InstrumentedFilter.REGISTRY_ATTRIBUTE,
                metricRegistry);
        servletContext.setAttribute(MetricsServlet.METRICS_REGISTRY,
                metricRegistry);

        log.debug("Registering Metrics Filter");
        FilterRegistration.Dynamic metricsFilter = servletContext.addFilter("webappMetricsFilter",
                new InstrumentedFilter());

        metricsFilter.addMappingForUrlPatterns(disps, true, "/*");
        metricsFilter.setAsyncSupported(true);

        log.debug("Registering Metrics Servlet");
        ServletRegistration.Dynamic metricsAdminServlet =
                servletContext.addServlet("metricsServlet", new MetricsServlet());
        metricsAdminServlet.addMapping("/management/metrics/*");
        //metricsAdminServlet.setInitParameter("com.codahale.metrics.servlets.MetricsServlet.allowedOrigin", "*");
        metricsAdminServlet.setAsyncSupported(true);
        metricsAdminServlet.setLoadOnStartup(2);
    }

    @Autowired(required = false)
    public void setMetricRegistry(MetricRegistry metricRegistry) {
        this.metricRegistry = metricRegistry;
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = appProperties.getCors();
        if (config.getAllowedOrigins() != null && !config.getAllowedOrigins().isEmpty()) {
            log.debug("Registering CORS filter");
            source.registerCorsConfiguration("/api/**", config);
            source.registerCorsConfiguration("/management/**", config);
            source.registerCorsConfiguration("/v2/api-docs", config);
        }
        return new CorsFilter(source);
    }
}
